Estuarine biofilm patterns: Modern analogues for Precambrian self-organization |
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| Authors: | Roeland C van de Vijsel Jim van Belzen Tjeerd J Bouma Daphne van der Wal Valentina Cusseddu Sam J Purkis Max Rietkerk Johan van de Koppel |
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| Institution: | 1. NIOZ Royal Netherlands Institute for Sea Research, Department of Estuarine and Delta Systems, and Utrecht University, PO Box 140, Yerseke, NL-4400 AC, The Netherlands;2. Dipartimento di Scienze della Natura e del Territorio, Polo Bionaturalistico, University of Sassari, Via Piandanna 4, 07100 Sassari, Italy;3. CSL – Center for Carbonate Research, Department of Marine Geosciences, RSMAS, University of Miami, 4600 Rickenbacker Causeway, Miami, FL, 33149 USA;4. Copernicus Institute, Department of Environmental Sciences, Utrecht University, PO Box 80115, 3508 TC, Utrecht, The Netherlands |
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| Abstract: | This field and laboratory study examines whether regularly patterned biofilms on present-day intertidal flats are equivalent to microbially induced bedforms found in geological records dating back to the onset of life on Earth. Algal mats of filamentous Vaucheria species, functionally similar to microbial biofilms, cover the topographic highs of regularly spaced ridge–runnel bedforms. As regular patterning is typically associated with self-organization processes, indicators of self-organization are tested and found to support this hypothesis. The measurements suggest that biofilm-induced sediment trapping and biostabilization enhance bedform relief, strength and multi-year persistence. This demonstrates the importance of primitive organisms for sedimentary landscape development. Algal-covered ridges consist of wavy-crinkly laminated sedimentary deposits that resemble the layered structure of fossil stromatolites and microbially induced sedimentary structures. In addition to layering, both the morphological pattern and the suggested formation mechanism of the recent bedforms are strikingly similar to microbialite strata found in rock records from the Precambrian onwards. This implies that self-organization was an important morphological process in times when biofilms were the predominant sessile ecosystem. These findings furthermore emphasize that self-organization dynamics, such as critical transitions invoking ecosystem emergence or collapse, might have been captured in fossil microbialites, influencing their laminae. This notion may be important for paleoenvironmental reconstructions based on such strata. © 2019 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd |
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| Keywords: | biogeomorphology long-term morphodynamics ridges and runnels bedforms biostabilization biofilms algal mats self-organization autogenic dynamics stromatolites microbially induced sedimentary structures microbialites sedimentary record paleoenvironment |
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